Remove the FF ci_refactoring_pipeline_schedule_create_service

What does this MR do and why?

This MR removes the FF ci_refactoring_pipeline_schedule_create_service.

• Related to #416359 (closed)
• Introduced in !124696 (merged).
• Fully rolled out on GitLab.com since 6th July 2023.

MR acceptance checklist

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• I have evaluated the MR acceptance checklist for this MR.